In an era of gay marriage and a black president, more than a half-century after the Civil Rights Act of 1964 became law, separatists can’t exactly swan dive into conversations with strangers about the white-power cause.

But Rachel Pendergraft — the national organizer for the Knights Party, a standard-bearer for the Ku Klux Klan — told The Washington Post that the KKK, for one, has a new conversation starter at its disposal.

You might call it a “Trump card.”

It involves, say, walking into a coffee shop or sitting on a train while carrying a newspaper with a Donald Trump headline. The Republican presidential candidate, Pendergraft told The Post, has become a great outreach tool, providing separatists with an easy way to start a conversation about issues that are important to the dying white supremacist movement.

“One of the things that our organization really stresses with our membership is we want them to educate themselves on issues, but we also want them to be able to learn how to open up a conversation with other people,” Pendergraft said.

Using Trump as a conversation piece has been discussed on a private, members-only website and in “e-news, stuff that goes out to members.”

In addition to opening “a door to conversation,” she said, Trump’s surging candidacy — which has the support of former KKK Grand Wizard David Duke, among others — has done something else: It has electrified some members of the movement.

“They like the overall momentum of his rallies and his campaign,” Pendergraft said. “They like that he’s not willing to back down. He says what he believes and he stands on that.”

For large numbers of Americans, Trump’s blunt rhetoric surrounding immigration, minority groups and crime may sound like finely tuned retrograde vitriol. But for Pendergraft and a growing number of white nationalists flocking to the campaign’s circus-like tent, the billionaire sounds familiar, like a man fluent in the native tongue of disaffected whites.

It’s a language people such as Pendergraft never thought they’d hear a mainstream politician in either party use in public.

And they’re desperately hoping Trump’s rise from reality-show figure to Republican front-runner may be the beginning of something that transcends the campaign trail.

The same rhetoric that frightens critics (“Trump has really lifted the lid off a Pandora’s box of real hatred and directed it at Muslims,” said the Southern Poverty Law Center’s Mark Potok) draws praise from supporters such as Duke, the former KKK leader and Louisiana politician.

The support Trump has received from Duke has drawn new scrutiny in recent days. Asked Sunday by CNN’s Jake Tapper to “unequivocally condemn” Duke, Trump pleaded ignorance.

“Just so you understand, I don’t know anything about David Duke, OK?” Trump said.

Tapper pressed him several more times to disavow Duke and the KKK, but Trump again declined.

“I don’t know anything about what you’re even talking about with white supremacy or white supremacists,” he said. “So I don’t know. I don’t know — did he endorse me, or what’s going on? Because I know nothing about David Duke; I know nothing about white supremacists.”

On his radio show last week, Duke encouraged listeners to cast their ballots for the candidate, saying that “voting against Donald Trump at this point is really treason to your heritage.”

“I’m not saying I endorse everything about Trump, in fact I haven’t formally endorsed him,” Duke said, in remarks reported by Buzzfeed. “But I do support his candidacy, and I support voting for him as a strategic action. I hope he does everything we hope he will do.”

Two days before his interview with Tapper, Trump brushed off Duke’s support, telling reporters in Texas on Friday: “David Duke endorsed me? OK, alright. I disavow, OK?”

On Monday — after saying “I know nothing about David Duke; I know nothing about white supremacists” — Trump told the “Today” show that his refusal to disavow Duke a day earlier was the result of a “very bad earpiece.”

“I’m sitting in a house in Florida with a very bad earpiece that they gave me, and you could hardly hear what he was saying,” Trump said. “But what I heard was various groups, and I don’t mind disavowing anybody, and I disavowed David Duke and I disavowed him the day before at a major news conference, which is surprising because he was at the major news conference, CNN was at the major news conference, and they heard me very easily disavow David Duke.

“Now, I go, and I sit down again, I have a lousy earpiece that is provided by them, and frankly, he talked about groups. He also talked about groups. And I have no problem with disavowing groups, but I’d at least like to know who they are. It would be very unfair to disavow a group, Matt, if the group shouldn’t be disavowed. I have to know who the groups are. But I disavowed David Duke.”

When Bloomberg’s Mark Halperin and John Heilemann asked whether he would repudiate Duke’s support, Trump replied: “Sure, I would if that would make you feel better.”

Trump’s campaign has not respond to multiple requests from The Post seeking comment about the candidate’s support among white supremacists.

The candidate does not endorse white supremacist groups, and his campaign fired two staffers last year for posting racially offensive material on social media. Trump also shocked some conservatives by criticizing Justice Antonin Scalia after Scalia argued last year that black students would perform better in “slower-track” universities.

“I thought it was very tough to the African American community, actually,” Trump told CNN.

For years, Trump has bragged about having a “great relationship with the blacks.” Last year, he held private meetings with dozens of African American evangelical pastors at Trump Tower in Manhattan and later told reporters he saw “love in that room.”

But the meeting was subsequently criticized by more than 100 black ministers, theologians and religious activists, who penned a letter questioning why their colleagues would agree to sit down with a candidate who “routinely uses overtly divisive and racist language on the campaign trail.”

Donald Trump peers out into the crowd during a campaign event at the International Air Response facility in Mesa, Ariz., on Dec. 16. (Ralph Freso/Getty Images)

As this primary season of fear and anger has progressed, Trump’s rallies have occasionally made headlines for rowdy, mostly white crowds and ugly outbursts.

In September, the leader of Trump’s personal security team punched an immigration demonstrator in the head after grabbing a sign reading, “Trump: Make America Racist Again.” In November, a Black Lives Matter protester said he was beaten at a Trump rally and said attendees used a racial slur during the attack.

In December, at a Trump campaign event in Arizona, The Post reported, a man shouted “motherf——– tacos!” at two Latino protesters. A person at another rally in December, in Las Vegas, could be heard yelling “Sieg heil!” — a verbal salute used by the Nazis.

“I urge you to vote for Donald Trump because he is the one candidate who points out that we should accept immigrants who are good for America,” Taylor says on the recording, which was paid for by the American National super PAC. “We don’t need Muslims. We need smart, well-educated white people who will assimilate to our culture. Vote Trump.”

Taylor told The Post that he finds Trump’s rhetoric on immigration appealing, even though he doesn’t particularly care for the candidate’s brash style.

“I think what he’s done is a very important thing,” Taylor told The Post. “He’s the first candidate in decades to say almost explicitly that immigration should be in the interest of Americans and not just immigrants.”

He added: “He’s attractive to many Americans who see their country slipping through their fingers. You don’t want to end your days living in an outpost of Haiti or Guatemala do you?”

During Trump’s meteoric rise to the top of the Republican field, white supremacist groups have enthusiastically embraced him.

Stormfront, one of the most popular white nationalist websites, claims that a surge of Trump-inspired traffic has forced administrators to upgrade their servers, according to Politico.

Site founder Don Black told The Post that Trump has “inspired an insurgency” for users of the site and listeners of a Stormfront radio show.

“It’s all very surprising to me,” Black said. “I would have never expected he be the great white hope, of all people. But it’s happening. So that’s what we talk about. That’s what so many of our people are inspired by.”

In a recent post on the white nationalist blog Occidental Observer, Kevin MacDonald — described by the Southern Poverty Law Center as “the neo-Nazi movement’s favorite academic” — wrote that Trump’s candidacy is helping America realize that a “very large number of White people are furious” about the where the country is headed.

“We are living in very exciting times,” MacDonald wrote. “A major political candidate is saying things that have been kept out of the mainstream for decades by a corrupt elite consensus on immigration and multiculturalism that dominates both the GOP and the Democrats.”

MacDonald called Trump’s candidacy “a game changer” that “has a very real possibility of success,” adding:

In this new climate, millions of White people are realizing that it’s entirely legitimate to oppose immigration and multiculturalism.

It’s okay to oppose the idea that every last human has the moral right to immigrate to a Western country, or that all peoples and cultures are equally acceptable as immigrants. And it’s safe to say that millions of White people are changing what they think.

“I don’t think Trump is a white nationalist,” National Policy Institute director Richard Spencer told the New Yorker. But Spencer, called “one of the country’s most successful young white nationalist leaders” by the SPLC, told the New Yorker that Trump reflects “an unconscious vision that white people have — that their grandchildren might be a hated minority in their own country. I think that scares us. They probably aren’t able to articulate it. I think it’s there.”

He added: “I think that, to a great degree, explains the Trump phenomenon. I think he is the one person who can tap into it.”

During the embryonic days of the campaign — way back when Trump was still known more for televised business deals than anything-goes bombast — Matthew Heimbach was like many conservative voters: uninterested in Trump.

But several months later, the 24-year-old said he found himself caught in an all-powerful Trumpian tractor beam.

“It’s exciting to see, and I didn’t expect it,” Heimbach told The Post.

How did that happen, exactly?

The same way it has for millions of other conservatives, who have been drawn to the candidate’s outspoken and seemingly unscripted rhetoric aimed at working-class voters already seething about poor economic prospects, the “menace” of illegal immigration and the persistent threat of violent crime.

And yet, Heimbach is no ordinary conservative.

He’s an influential and avowed white nationalist, a divisive and radical outsider who gave up on mainstream politicians years ago. As a polarizing student at Towson University, Heimbach made headlines by unsuccessfully attempting to establish a White Student Union and leading controversial night patrols to combat a so-called “black crime wave,” according to the SPLC, which monitors hate speech.

The onetime member of the neo-Confederate League of the South never thought he’d be back under the Republican umbrella.

But then Trump began talking about “building a great, great wall on our southern border.”

“This is the first time since Buchanan in the ’90s and George Wallace in ’68 where you have a guy outside the mainstream speaking to white interests,” Heimbach told The Post.

“Donald Trump, whether he meant to or not, has opened this floodgate that I don’t think can be restrained regardless of what happens in the 2016 elections,” Heimbach added.

Trump didn’t exactly create this new wave of radical support, according to the Southern Poverty Law Center’s Potok.

What Trump is doing, Potok told The Post, is taking a “subterranean community” of people that, until recently, existed underground and online and bringing them into the light of mainstream America. Hostile towards minority groups, fearful of seismic changes in racial demographics and cultural norms, and frustrated by corrupt politicians they perceive as cowed by politically correct culture, it is a bloc of Americans who have been quietly seething, Potok said.

“Even 15 years ago, same-sex marriage is something that seemed unimaginable, and now it’s the law of the land,” he said. “For a pretty sizable number of Americans, that’s unbelievable. They feel like ground is being cut from under them, like they inhabit a world they don’t recognize.”

Trump, Potok said, has opened a conversation about an America that never really existed. That conversation might include factually incorrect information, such as a tweet last month showing an image of a dark-skinned man holding a handgun above a series of inflammatory statistics that Politifact described as “wildly inaccurate.”

Originally posted by a neo-Nazi, the information was disseminated by Trump one day after Trump supporters assaulted a black activist at a rally in Alabama.

But accuracy and basis in reality aren’t what matter to some of Trump’s supporters, Potok said.

“What his statements do is open up a political space for people that have these radical feelings and he gives them permission to speak out, loudly and proudly,” he said. “Accuracy is beside the point.”

Marilyn Mayo, co-director of the Anti-Defamation League’s Center on Extremism, said it’s difficult to verify white supremacist claims that Trump is drawing new members into their ranks because their ranks are closely held secrets.

What is verifiable, she said, is the surge in postings on websites such as Stormfront each time Trump makes a controversial statement.

That excitement, she noted, stems from the belief among white supremacists that a front-runner is knowingly championing their agenda by using both explicit and coded language.

“These groups are constantly trying to reach whites that they think would be attracted if they were just inspired enough,” Mayo told The Post. “What it does is allow the mainstreaming of hate.”

“They’re using Trump and his message to bring more people and more money into their fold, and that’s a tremendous concern.”

Jose A. DelReal contributed to this post, which was originally published in December 2015 and has been updated.